Pearson appeared on The Ultimate Fighter: United States vs. United Kingdom. He defeated A.J. Wenn by knockout in an elimination match earning him a trip to Las Vegas, Nevada to compete on the show. Pearson inarguably controlled the first round against Wenn, leading Dana White and other observers of the fight at ringside to predict that Wenn wouldn't come out of his corner for the second round. Pearson finished the fight early in the second round. Pearson had his second fight against Team United States fighter Richie Whitson. Pearson defeated Whitson via a first round armbar.

Pearson won his semi-final fight against Jason Dent via unanimous decision. The win put Pearson into the finals against his teammate Andre Winner.

Pearson had a professional record of 8–3 when he entered The Ultimate Fighter house. One of those losses was a decision loss to Abdul Mohammed on the now-defunct Cage Gladiators show in Liverpool. The decision was extremely controversial and Pearson's managers openly accused the promotion's judges of being biased towards Mohammed, who was fighting out of the Wolfslair Academy and was thus the hometown fighter. The promoter's decision to remove the fight from a subsequent television broadcast of the event it took place on was also seen as a suspicious act. Pearson's camp refused to allow any more of their fighters to compete on Cage Gladiators events.[6]

At UFC 105, Pearson had his next UFC fight against veteran Aaron Riley. Pearson controlled the fight, and never looked troubled by the offense of Riley and was able to demonstrate varied strikes throughout the fight. After the fight was paused in the second round following a flying knee to the head of Riley; doctors viewed the cuts on Riley's face and came to the conclusion that he was unable to continue.

Pearson defeated kickboxerDennis Siver by unanimous decision (30–27, 30–27, 30–27) on 31 March 2010 at UFC Fight Night 21.[7] The bout was entertaining all three rounds with both fighters showing interesting stand-up skills. The bout received Fight of the Night honours, giving both fighters an extra $30,000.

Pearson faced Melvin Guillard on 26 October 2013 at UFC Fight Night 30.[18] The fight ended in a no contest when Pearson was deemed unable to continue after being cut on the forehead by an accidental illegal knee.[19]

A rematch with Guillard was expected to take place on 8 March 2014 at UFC Fight Night 37. However, Pearson pulled out of the bout citing a knee injury and was replaced by Michael Johnson.[20]

Pearson faced Diego Sanchez on 7 June 2014 at UFC Fight Night 42.[21] Despite seemingly controlling the action over the bout's duration, Pearson lost the fight via split decision.[22] 13 of 14 media scorecards had the bout 30-27 Pearson, while the 14th had Pearson winning 29-28.[23] As a result, Pearson filed an appeal with the New Mexico Athletic Commission, "in hopes the decision is overturned, at the very least to a no-contest."[24] The official decision was ultimately upheld.[25] Despite an official loss on the scorecards, UFC president Dana White indicated that the organization has ruled out the possibility of an immediate rematch and said that they will informally treat it as a win for Pearson and that he would be compensated that way.[26]

Pearson was expected to face Abel Trujillo on 16 August 2014 at UFC Fight Night 47.[27] However, on 4 August, Trujillo pulled out of the Pearson bout and was replaced by Gray Maynard.[28] He won the fight by TKO in the second round. After a close first round, Early in the second round Pearson tagged Maynard with nice combinations and dropped him with Maynard not intelligently defending himself and then ref Keith Peterson stepped in to stop the fight.